and may be suitable candidates for reduced intensity pre- or postoperative chemotherapy, according to a team of European investigators.
Among 441 women in a Dutch cancer registry who were younger than 40 when they were diagnosed with node-negative TNBC and had not undergone systemic therapy, those who had 75% or more TILs in the intratumoral stromal area had a 15-year cumulative incidence of distant metastases or death of just 2.1%, and every 10% increase in sTILs was associated with a 19% decrease in the risk of death.
In contrast, the 15-year cumulative incidence of distant metastases was 38.4% for women with stromal TIL scores of less than 30%, according to researchers writing in the Journal of Clinical Oncology.
“These data could be used as a starting point for designing a randomized controlled chemotherapy de-escalation trial. The current study confirms the importance of sTILs as a valuable addition to the set of standard prognostic factors in patients with TNBC,” wrote the researchers, who were led by Sabine C. Linn, MD, of the Netherlands Cancer Institute, Amsterdam.
Markers for immune response
Stromal TILs, a mixture of mononuclear immune cells, have been shown in previous studies to be prognostic for outcomes in patients with early-stage TNBC treated either with or without neoadjuvant or adjuvant chemotherapy.
For example, investigators cited a study published in JCO in 2014, that showed among women with TNBC enrolled in the phase 3 ECOG 2197 clinical trial and the related ECOG 119 clinical trial, after a nearly 11-year follow-up, higher sTIL scores were associated with significantly better prognosis with every 10% increase translating into a 14% reduction in the risk of recurrence or death (P = .02).
“The prognostic importance of sTILs is, however, unexplored in patients diagnosed under age 40 years, let alone in the subgroup of systemic therapy–naive patients,” Dr. Linn and colleagues wrote.
Retrospective study
To see whether the prognostic value of sTILs was as strong among young, systemic therapy–naive women, the investigators conducted a retrospective study of women enrolled in the Netherlands Cancer Registry who were diagnosed with node-negative TNBC from 1989 to 2000. The patients selected had undergone only locoregional treatment, including axillary node dissection, but had not received any systemic therapy.
Pathologists reviewed samples, with TILs reported for the stromal compartment. The samples were grouped by sTIL score categories of high (75% or greater), intermediate (30% to less than 75%), or low (less than 30%). The investigators looked at overall survival (OS) and distant metastasis-free survival (DMFS) stratified by sTIL scores,
During a median follow-up of 15 years, 107 women died or developed distant metastases, and 78 experienced a second primary cancer.
The results were as noted, with patients in the highest category of sTILs having very low rates of either death or distant metastases during follow-up.
“We confirm the prognostic value of sTILs in young patients with early-stage N0 TNBC who are systemic therapy naive by taking advantage of a prospectively collected population-based cohort. Increasing sTILs are significantly associated with improved OS and DMFS. Patients with high sTILs (> 75%) had an excellent 10-year overall survival and a very low 10-year incidence of distant metastasis or death.
The study was supported by grants from The Netherlands Organization for Health Research and Development, A Sister’s Hope, De Vrienden van UMC Utrecht, Agilent Technologies, the Dutch Cancer Society, and Breast Cancer Research Foundation. Dr. Linn reported consulting with and receiving compensation from Daiichi Sankyo, as well as receiving research funding from Genentech/Roche, AstraZeneca, Bristol-Myers Squibb, Tesaro, Merck, Immunomedics, Eurocept Pharmaceuticals, Agendia, and Novartis.